JP2008259094A - Wireless lan telephone communication method and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless LAN telephone communication method and system which effectively utilize a communication band and have high quality of calls. <P>SOLUTION: A means is provided for duplicating a generated voice packet, prestoring one or more copies and collectively transmitting copies of one or more voice packets, generated prior to and a voice packet generated recently to one radio frame in transmission; and a means is provided for dividing a packet into original packets at a receiving side. Even if burst errors occur which may frequently occur on a wireless LAN, a voice packet is made redundant and transmitted, such that it is not necessary to perform retransmission. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless LAN telephone communication method and system using a wireless LAN.

  In recent years, IP telephones using VoIP technology have become widespread. IP phones packetize voice and send and receive voices over the Internet and dedicated networks, so call costs are low, and major providers offer services in various regions, so recently not only companies It has been used in many homes. Recently, there has also been a movement to make IP telephones cordless. For example, a product has been announced in which the parent device terminates the IP telephone protocol, and the parent device transmits the voice to the child device using a conventional cordless telephone system. In addition, the IP phone protocol is not terminated at the master unit, but can be terminated at the slave unit, and the slave unit can be brought to a public wireless access point such as a hotspot to make a cheap call. A cordless telephone using a wireless LAN has also been proposed.

  A conventional wireless LAN telephone will be described with reference to the drawings.

FIG. 38 is a diagram showing a state in which voice packets are transmitted from the parent device to the child device during a conventional wireless LAN telephone call. In conventional wireless LAN telephones, voice packets are associated with wireless frames on a one-to-one basis. When an error occurs, it is specified that error recovery is performed by retransmission according to the IEEE 802.11 standard. When an error occurs, the radio frame is retransmitted (see, for example, Patent Document 1).
JP 2002-247647 A

  However, in the above-described conventional configuration, when an error actually occurs in wireless communication having a higher error rate compared to wired communication, retransmission must be performed, so the communication band cannot be used effectively, and retransmission is not performed. When this is done, there is a problem that the voice is delayed and the call quality is deteriorated.

  An object of the present invention is to provide a wireless LAN telephone communication method and system that effectively uses a communication band and has high call quality.

  The present invention duplicates a generated voice packet and saves one or more copies, and at the time of transmission, copies of one or more previously generated voice packets and recently generated voice packets into one radio frame. Means for transmitting the data collectively and means for dividing the packet into the original packets are provided on the receiving side.

  According to this configuration, even if a burst error that often occurs in a wireless LAN occurs, voice packets are redundantly transmitted, so there is no need to retransmit, there is no interruption or delay in sound, and there is no call. A high-quality wireless LAN telephone communication method and system can be provided.

  According to the present invention, even if a burst error that frequently occurs in wireless LAN communication occurs, voice packets are redundantly transmitted, so there is no need to retransmit, and there is no sound interruption or delay. High call quality can be achieved.

  The present invention duplicates a generated voice packet and saves one or more copies, and at the time of transmission, copies of one or more previously generated voice packets and recently generated voice packets into one radio frame. Means for transmitting the data collectively and means for dividing the packet into the original packets are provided on the receiving side.

  As a result, even if burst errors that often occur in wireless LANs occur, voice packets are redundantly transmitted, so there is no need to retransmit, providing high call quality without sound interruption or delay can do.

  In addition, the waiting time for transmission from the allowable delay time of voice, the codec period of voice, the codec delay of voice, and the scheduled transmission time of the radio frame determined by a predetermined network delay amount and a predetermined algorithm. Within the permissible range of the transmission waiting time, the voice packets are made redundant and a plurality of voice packets are transmitted together in one radio frame, and on the receiving side, a plurality of redundant voice packets are restored. It may be configured to be decomposed into

  As a result, the maximum redundancy is performed within the allowable delay time of the voice, so that it is possible to provide high call quality with no voice interruption or delay even in a communication environment with a high error rate.

  In addition, voice packets are stored in a queue within a voice delay allowable time, and two or more non-consecutive voice packets are selected by a predetermined algorithm, and are transmitted together in one radio frame. It may be configured.

  Thereby, since voice packets are interleaved, it is possible to provide a call resistant to burst errors.

  Further, the network delay may be measured and adapted to the network delay.

  As a result, even if the network traffic changes and the amount of delay changes, the transmission waiting time that can be tolerated on the transmission side can be adjusted, so that it is possible to provide a high-quality call that is not affected by changes in the network.

  In addition, a reception history buffer and a duplicate packet search unit may be provided so that voice packets received redundantly on the receiving side may be discarded.

  As a result, unnecessary voice packets (duplicate voice packets) are prevented from flowing through the network, so that it is possible to provide a good communication environment that does not impose network traffic.

  In addition, when a plurality of voice packets are combined into one radio frame, the upper protocol header may be analyzed to degenerate the redundant header of the upper protocol.

  Thereby, since redundant data is compressed, it is possible to provide a high-quality communication environment that does not compress the wireless communication band.

  Further, the communication error rate may be monitored, and it may be configured to select whether or not the voice packet is made redundant and transmitted according to the error rate.

  Thereby, since redundancy is performed only when the error rate is high, it is possible to provide a good communication environment that does not place an extra load on the wireless communication band in an environment with a low error rate.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
First, the wireless LAN telephone device slave unit will be described.

  FIG. 1 is a functional block diagram showing a wireless LAN telephone device slave unit according to the first embodiment of the present invention.

  In FIG. 1, 101 is an operation unit for designating a call destination, instructing a call at the time of an incoming call, and an instruction for terminating a call, 102 is a voice input unit for inputting a voice, and 103 outputs a voice. An audio output unit 104 for storing data received from the received radio frame, a transmission buffer 105 for storing data for radio transmission, and 107 for storing data stored in the transmission buffer 105. A radio communication unit 108 for transmitting a radio frame and receiving a radio frame and storing the contents of the frame in the reception buffer 104 is an RTC for measuring the passage of time.

  109 is a parameter storage unit that stores the codec period of the audio, 110 is A / D converted audio input from the audio input unit 102, and is converted (encoded) into audio packets using a predetermined algorithm. The codec unit 111, which decodes the data using a predetermined algorithm, performs D / A conversion, and outputs the data to the audio output unit 103, is the time when the encoding of the audio packet encoded by the codec unit 110 is completed, that is, transmission A transmission packet queue 112 that stores the request reception time in a FIFO manner together with a payload integration unit 113 that writes packets input to the transmission packet queue 111 within a transmission waiting time into one wireless frame and writes them in the transmission buffer. Decompose data received as wireless frames into packets The reception packet queue 114, which is stored in the IFO method, determines whether or not the contents stored in the reception buffer 104 were originally one packet. If a plurality of packets are integrated, the packet is decomposed into a plurality of packets. And a payload dividing unit for writing into the reception packet queue 113 by the FIFO method.

  116 is a call controller that controls outgoing / incoming calls, call connection / disconnection, and dial tone, busy tone, ringer, ring back tone according to the state of each call to the voice output unit 103, 117 is a protocol processing unit that processes call setting and cancellation and voice packet transmission / reception during a call according to a designated protocol; 118 is a higher-level protocol analysis unit; and 119 is an error in wireless communication An error rate determination unit 130 that calculates a rate and determines whether the error rate is lower than a predetermined error rate is a control unit that controls the whole.

  FIG. 2 is a device block diagram showing the wireless LAN telephone device slave unit according to the first embodiment of the present invention.

  In FIG. 2, 201 is a central processing unit (hereinafter referred to as CPU), 202 is ROM, 203 is RAM, 204 is RTC, 205 is baseband, 206 is RF, 207 is A / D. , 208 is a microphone, 209 is a D / A, 210 is a speaker, 211 is a keyboard, and 212 is a codec.

  1 and 2, the operation unit 101 is realized by the keyboard 211, the voice input unit 102 by the microphone 208, and the voice output unit 103 by the speaker 210.

  104 reception buffers, 105 transmission buffers, 109 parameter storage units, 111 transmission packet queues, and 113 reception packet queues are realized by 203 RAMs.

  The wireless communication unit 107 is realized by 205 baseband and 206 RF. In addition, 108 RTCs are realized by 204 RTCs, and 110 codecs are realized by 212 codecs, 207 A / Ds, and 209 D / As.

  112 payload integration unit, 114 payload division unit, 116 call control unit, 117 protocol processing unit, 118 high-level protocol analysis unit, 119 error rate determination unit, and 130 control unit are provided by 201 CPU. The program stored in the ROM 202 is executed while referring to the data stored in the 202 ROM, referring to or changing the data stored in the 203 RAM. Has been realized.

  Next, the wireless LAN telephone device base unit will be described.

  FIG. 3 is a functional block diagram showing the wireless LAN telephone apparatus master according to the first embodiment of the present invention.

  In FIG. 3, 104 is a reception buffer for accumulating data extracted from received radio frames, 105 is a transmission buffer for accumulating data for radio transmission, and 106 is a LAN communication unit for connecting to a wired network. 107 is a wireless frame for transmitting the data accumulated in the transmission buffer 105 into a radio frame and transmitting the data, and a radio communication unit for receiving the radio frame and storing the contents of the frame in the reception buffer 104. 108 for measuring the passage of time RTC.

  111 is a transmission that is stored in the FIFO method together with a transmission request reception time in order to transmit the Ethernet (registered trademark) frame from the LAN side that is determined to be relayed by the wired-to-wireless bridge unit 120 described later as a wireless frame. A packet queue 112 is a payload integration unit 113 that combines packets input to the transmission packet queue 111 within a transmission waiting time into a single radio frame and writes the packet into the transmission buffer. 113 disassembles data received as a radio frame into packets. Then, the reception packet queue 114 stored by the FIFO method determines whether or not the content stored in the reception buffer 104 was originally one packet, and if a plurality of packets are integrated, this is converted into a plurality of packets. Disassemble, receive packet queue 113 FIFO The payload division unit 118 writes the upper protocol, the upper protocol analysis unit 119 calculates the error rate in the wireless communication, and determines whether the error rate is lower than the prespecified error rate. , 120 is a wired-wireless bridge unit that relays a frame between wired and wireless if necessary, and discards the frame otherwise, and 130 is a control unit that controls the whole.

  FIG. 4 is a device block diagram showing the wireless LAN telephone device base unit in the first embodiment of the present invention.

  In FIG. 4, 201 is a CPU, 202 is a ROM, 203 is a RAM, 204 is an RTC, 205 is a baseband, 206 is an RF, and 213 is a network I / F.

  3 and 4, the reception buffer 104, the transmission buffer 105, the transmission packet queue 111, and the reception packet queue 113 are realized by the RAM 203.

  The wireless communication unit 107 is realized by the baseband 205 and the RF 206, the RTC 108 is realized by the RTC 204, and the LAN communication unit 106 is realized by the network I / F 213.

  The payload integration unit 112, the payload division unit 114, the upper protocol analysis unit 118, the error rate determination unit 119, the wired-wireless bridge unit 120, and the control unit 130 store the programs stored in the ROM 202 by the CPU 201 in the ROM 202. This is realized by referring to the data stored in the memory, referring to the data stored in the RAM 203, or changing the data.

  Next, the overall configuration of the wireless LAN telephone system of the present invention will be described.

  FIG. 5 is a diagram showing a wireless LAN telephone system according to Embodiment 1 of the present invention.

  As shown in FIG. 5, the slave device A is under the control of the master device A, and similarly, the slave device B is under the control of the master device B. Base unit A and base unit B are each connected to the Internet. The base unit A and the base unit B have a bridge function, and relay a wireless frame from the slave unit as an Ethernet (registered trademark) frame to the Internet side using a LAN communication unit (wired). An Ethernet (registered trademark) frame from the Internet side is relayed as a wireless frame to the slave unit.

  Regarding the wireless LAN telephone system configured as described above, the operations of the master unit and the slave unit will be described with reference to the sequence chart of FIG.

  The operation described below refers to a protocol called SIP that is often used in VoIP in recent years. However, in order not to make the description unnecessarily complicated, the process is somewhat simplified. In addition, here, explanation will be given with an emphasis on the cooperation between the parent device and the child device. Details of “encoding” and “decoding” of the slave unit, “bridge processing” of the master unit, and “wireless transmission” and “wireless reception” of the master unit and slave unit will be described later. In the present embodiment, it is assumed that the slave unit is initially in a standby state.

Step E01
First, the user of the slave unit A uses the operation unit 101 of the slave unit A to specify a call destination (step E01). Here, it is assumed that the user inputs a call destination number 050-1001-1234 from the operation unit 101 and instructs the call.

Step M02
The control unit 130 receives the call destination number input from the operation unit 101 and requests the call control unit 116 to set a call to the specified call destination number. The call control unit 116 creates an “INVITE” message to notify the slave unit B of the “call connection request” and requests the protocol processing unit 117 to transmit it to the slave unit B. The protocol processing unit 117 transmits data indicating “INVITE” to the parent device A through the wireless communication unit 107 (details will be described later as “child device transmission processing”). Base unit A converts the received wireless frame into a wired Ethernet (registered trademark) frame and transmits it to the Internet (details will be described later as “base unit bridge processing”). The Ethernet (registered trademark) frame transmitted from the parent device A arrives at the parent device B through the Internet (not shown). The base unit B relays the received Ethernet (registered trademark) frame, converts it into a radio frame, and transmits it to the handset B (details will be described later as “base unit bridge processing”). The slave unit B receives the radio frame transmitted from the master unit B, and notifies the call control unit 116 of the “INVITE” message via the radio communication unit 107 and the protocol processing unit 117 (for details, refer to “Slave unit reception process”). As described below). As a result, handset B has received the call.

Step E03
In the slave unit B, the call control unit 116 requests the codec unit 110 to play a ringer (ringing tone). Then, the codec unit 110 outputs the voice stored in the voice output unit 103 as a ringtone.

Step M04
In the slave unit B, the call control unit 116 creates a “RINGING” message and requests the protocol processing unit 117 to transmit to the slave unit A in order to notify the slave unit A that “the incoming call has been accepted”. The protocol processing unit 117 transmits data meaning “RINGING” to the parent device B via the wireless communication unit 107. This data is converted from a radio frame to an Ethernet (registered trademark) frame by the master unit B, and reaches the master unit A through the Internet. Further, the parent device A relays the received Ethernet (registered trademark) frame and transmits it to the child device A as a wireless frame.

Step E05
In the slave unit A, the call control unit 116 receives the “RINGING” message via the wireless communication unit 107 and the protocol processing unit 117, and knows that the call destination has accepted the incoming call. The call control unit 116 requests the codec unit 110 to output a ring back tone (ringing tone, hereinafter abbreviated as RBT). Then, the codec unit 110 outputs the RBT to the audio output unit 103.

Step E06
In slave unit B, when the user hears the ringer and notices that he / she is receiving a call, he / she operates the operation unit 101 to instruct a call. Then, in the handset B, the control unit 130 receives a message “instructed to talk” from the operation unit 101 and requests the call control unit 116 to “connect the call”.

Step M07
In the slave unit B, the call control unit 116 creates a “CONNECT-OK” message to notify the slave unit A that “the user has responded to the incoming call”, and transmits the message to the slave unit A. Request to 117. The protocol processing unit 117 transmits data indicating “CONNECT-OK” to the parent device B via the wireless communication unit 107. Then, the master unit B converts the radio frame received from the slave unit B into an Ethernet (registered trademark) frame and relays it, and the Ethernet (registered trademark) frame reaches the master unit A through the Internet. In the master unit A, the received Ethernet (registered trademark) frame is converted into a radio frame, relayed, and transmitted to the slave unit A. In the slave unit A, the call control unit 116 receives “CONNECT-OK” via the wireless communication unit 107 and the protocol processing unit 117, and requests the codec unit 110 to stop the RBT. Then, the codec unit stops the RBT.

Step E08
Thereafter, a full-duplex communication path is secured, and a call becomes possible. Here, it is assumed that the communication band of the Internet is sufficiently wide and the delay is about several tens of ms. That is, it is assumed that the bottleneck for communication between the slave unit A and the slave unit B is between the slave unit and the master unit.

Step M09
During a call, the voice of the user of the slave unit A is input to the voice input unit 102 of the slave unit A, encoded by the codec unit 110, and transmitted as a voice packet to the slave unit B by the protocol processing unit 117. In the slave unit B, the codec unit 110 receives the voice packet via the wireless communication unit 107 and the protocol processing unit 117, decodes it, and outputs the result to the voice output unit 103 of the slave unit B. Since the process in which the user's voice from the handset B side reaches the handset A is a process that is exactly symmetric to the above-described process, a description thereof will be omitted.

Step E10
The user of the slave unit B instructs the call disconnection from the operation unit 101 to end the call. Then, the control unit 130 receives a call disconnection instruction from the operation unit 101 and requests the call control unit 116 to disconnect the call. The call control unit 116 stops the encoding task and the decoding task. Then, the codec unit 110 stops the codec. Thereafter, even if a voice packet is received, it is discarded, and the voice input is not encoded.

Step M11
In the slave unit B, the call control unit 116 creates a “BYE” message and requests the protocol processing unit 117 to transmit it to the slave unit A. The protocol processing unit 117 transmits data indicating “BYE” to the parent device B via the wireless communication unit 107. As before, the “BYE” message arrives at the child device A via the parent device B, the Internet, and the parent device A.

Step E12
In the handset A, the call control unit 116 receives the “BYE” message via the wireless communication unit 107 and the protocol processing unit 117. The call control unit 116 stops the encoding task and the decoding task. Then, the codec unit 110 stops the codec. Thereafter, even if a voice packet is received, it is discarded, and no encoding is performed for voice input.

Step M13
In the slave unit A, the call control unit 116 creates a “BYE-OK” message and requests the protocol processing unit 117 to transmit it to the slave unit B. The protocol processing unit 117 transmits data indicating “BYE-OK” to the parent device A via the wireless communication unit 107. As before, the message “BYE-OK” reaches the child device B via the parent device A, the Internet, and the parent device B.

Step E14
In the slave unit B, the call control unit 116 receives the “BYE-OK” message via the wireless communication unit 107 and the protocol processing unit 117. Thereafter, the slave unit B enters the “standby mode”.

  Next, an outline of the operation of the slave unit of the present embodiment will be described.

  FIG. 7 shows a task configuration diagram of the slave unit in the first embodiment of the present invention.

  In this embodiment, an encoding task for encoding audio, a decoding task for decoding audio, a call control task for performing call setup / connection / disconnection, and wireless transmission for transmitting audio packets stored in the transmission packet queue as radio frames It is assumed that a task, a wireless reception task that receives a wireless frame, converts it into a voice packet, and writes it to the reception packet queue is operating in parallel. The encoding task, decoding task, and call control task make a transmission request and a reception request to the protocol processing task. After making the reception request, when the protocol processing task receives the requested data, the protocol processing task notifies the requesting task to that effect. In addition, the arrow in a figure has shown the flow of data.

  Next, an outline of the operation of the parent device in the present embodiment will be described.

  FIG. 8 shows a task configuration diagram of the parent device in the first embodiment of the present invention.

  In the master unit, as with the slave unit, the wireless transmission task, the wireless reception task, and “the wireless frame received by the wireless reception task should be examined to determine whether to relay the frame between wired and wireless. For example, after converting the format of the frame, an Ethernet (registered trademark) frame is transmitted via the LAN communication unit 106, and the Ethernet (registered trademark) frame received through the LAN communication unit 106 is examined, and wired and wireless It decides whether to relay frames between them, and if necessary, converts the frame format and then passes it to the wireless transmission task.

  Hereinafter, each task operation of the slave unit will be described using a flowchart.

  First, the encoding task process will be described with reference to the flowchart of FIG.

  The encoding task is activated during a call by a call control task. When the call ends, it is stopped by the call control task. The following description is the operation of the encoding task during a call.

Step S01
The codec unit 110 receives audio from the audio input unit 102, performs sampling (A / D conversion), and encoding.

Step S02
The codec unit 110 refers to the codec interval stored in the parameter storage unit 109 and determines whether or not encoding has been performed for the time specified by the codec interval while comparing with the RTC 108. If the designated time has elapsed, the process proceeds to step S03. Otherwise, the process returns to step S01.

Step S03
The codec unit 110 passes the sampled data to the protocol processing unit 117 and requests transmission. Return to step S01.

  Next, decoding task processing will be described with reference to the flowchart of FIG.

  The decode task is activated during a call by the call control task. When the call ends, it is stopped by the call control task. The following description is the operation of the decoding task during a call.

Step S101
The codec unit 110 confirms whether a reception notification is received from the protocol processing unit 117. If a reception notification has been received, the process proceeds to step S102. Otherwise, the process returns to step S101.

Step S102
The codec unit 110 receives received data from the protocol processing unit 117.

Step S103
The codec unit 110 refers to the RTP header of the received data and determines whether or not it matches the time stamp of the previous received data. If they match, the process proceeds to step S101; otherwise, the process proceeds to step S104.

Step S104
The codec unit 110 stores the time stamp written in the RTP header of the received data.

Step S105
The codec unit 110 decodes the received data, D / A converts the result, and outputs the output to the audio output unit 103. Return to step S101.

  Next, the operation of the call control task will be described with reference to the state chart of FIG.

  First, the operation of the call control task will be described from the side of the handset A with respect to a series of processes in which the handset A is turned on and the user of the handset A makes a call, talks, and disconnects.

Step E-1
When the operation unit 101 instructs to turn on the power of the slave unit, the control unit 130 activates a call control task, a protocol processing task, a wireless transmission task, and a wireless reception task. When the call control task is activated, it transitions to a standby state. Then, incoming and outgoing calls can be made thereafter.

Step E-2
The user operates the operation unit 101 on the child device A and makes a call to the child device B. The control unit 130 of the slave unit A receives the “call” notification from the operation unit 101, receives the call destination number, and requests the call control unit 116 to designate the other party number and make a “call connection” request. The call control unit 116 requests the protocol processing unit 117 to transmit the “INVITE” message to the child device B. The handset B accepts the “INVITE” message, becomes an incoming call, and returns a “RINGING” message to the handset A. The call control unit 116 of the child device A receives the “RINGING” message from the child device B via the protocol processing unit 117, and transitions to a calling state. The call control unit 116 outputs the RBT to the voice output unit 103 to inform the user that “calling”.

Step E-3
In cordless handset B, a ringer (ringing tone) is ringing, and the user notices the ringing tone and accepts the incoming call. Then, after the encoding task and the decoding task are activated, a “CONNECT-OK” message is transmitted to the child device A. In the slave unit A, the call control unit 116 receives the “CONNECT-OK” message via the protocol processing unit 117. Then, the call control unit 116 activates the above-described encoding task and decoding task, and the codec unit 110 performs A / D conversion and encoding on the subsequent voice from the voice input unit 102 and passes it to the protocol processing unit 117 as a voice packet. . Further, the codec unit 110 decodes and D / A converts the voice packet received by the protocol processing unit 117, and outputs it to the voice output unit 103. Transition during a call.

Step E-9
When the user of the slave unit A finishes the call, the operation unit 101 of the slave unit A is operated to disconnect the call. The control unit 130 receives a disconnection operation notification from the operation unit 101 and requests the call control unit 116 to perform “call disconnection”. The call control unit 116 stops the encoding task and the decoding task. Then, the call control unit 116 requests the protocol processing unit 117 to send a “BYE” message to the child device B. The protocol processing unit 117 transmits data indicating a “BYE” message to the parent device A via the wireless processing unit 107 and arrives at the child device B via the Internet and the parent device B. When the slave unit B receives the “BYE” message, it returns “BYE-OK” to the slave unit A. In the slave unit A, the call control unit 116 receives the “BYE-OK” message via the wireless communication unit 107 and the protocol processing unit 117. Then, a transition is made to the standby state.

Step E-7
When a user cancels a call while making a call, the operation unit 101 issues a call cancellation instruction, the control unit 130 receives a call cancellation instruction from the operation unit 101, and issues a call to the call control unit 116. Request cancellation. The call control unit 116 requests the protocol processing unit 117 to transmit a “CANCEL” message to the child device B. The handset B stops the ringer and sends a “CANCEL-OK” message to the handset A. In the slave unit A, when the protocol processing unit 117 receives “CANCEL-OK” from the slave unit B and notifies the call control unit 116, the call control unit 116 shifts to a standby state.

  Next, the operation of the call control task as seen from the handset B side will be described.

Step E-4
The protocol processing unit 117 receives the “INVITE” message from the child device A and notifies the call control unit 116 of the message. The call control unit 116 requests the protocol processing unit 117 to return a “RINGING” message to the child device A. The call control unit 116 outputs a ringer to the voice output unit 103 to inform the user that an incoming call has occurred. The call control unit 116 transitions to an incoming call state.

Step E-5
The user learns that the ringer is receiving a call and operates the operation unit 101 to answer the incoming call. The control unit 130 receives an incoming response from the operation unit 101 and requests the call control unit 116 for a response. Then, the call control unit 116 requests the protocol processing unit 117 to transmit a “CONNECT-OK” message to the child device A. The protocol processing unit 117 transmits a “CONNECT-OK” message to the child device A. Further, the call control unit 116 stops the ringer output to the audio output unit 103, starts the encoding task and the decoding task, and the audio from the subsequent audio input unit 102 is A / D converted / encoded, and the audio packet To the slave unit A, and the voice packet from the slave unit A is decoded and D / A converted and output from the voice output unit 103.

Step E-9
The protocol processing unit 117 receives the “BYE” message from the slave unit A and notifies the call control unit 116 of it. The call control unit 116 stops the encoding task and the decoding task, and transitions to a standby state.

  Further, when the user of the slave unit A cancels the call during the call, the following occurs.

Step E-8
The protocol processing unit 117 receives the “CANCEL” message and notifies the call control unit 116 of it. The call control unit 116 stops the ringer, requests the protocol processing unit 117 to transmit a “CANCEL-OK” message to the child device A, and transitions to a standby state.

  Next, the operation of the protocol processing task will be described with reference to the flowchart of FIG.

Step S121
The protocol processing unit 117 checks whether there is a transmission request from the encode task, the decode task, and the call control task. If there is, the process proceeds to step S122, and if not, the process proceeds to step S123.

Step S122
The protocol processing unit 117 receives a transmission request, adds a header according to each protocol, and puts it in the transmission packet queue 111. The transmission packet queue 111 is prepared for each destination. Here, the destination is a transmission destination MAC address defined in IEEE 802.11. At this time, the time at which this transmission request is received is written in association with the transmission request with reference to the RTC 108. The process proceeds to step S121.

  Here, a description will be given assuming that an audio packet is received from the encoding task. The protocol processing unit 117 adds an RTP header, UDP header, IP header, and LLC header to the voice packet and determines a destination MAC address (usually, the destination is given by an IP address, and the protocol processing unit 117 (The details are omitted because they are the same as normal TCP / IP communication processing.) The protocol processing unit 117 selects a transmission packet queue having a destination MAC address of the voice packet from the transmission packet queue 111 prepared for each MAC address, and puts the voice packet in the transmission packet queue 111. At this time, the RTC 108 is referred to and written in the transmission packet queue as the transmission request reception time. Proceed to step S121.

Step S123
The protocol processing unit 117 checks whether data has arrived at the reception packet queue 113. If it has arrived, the process proceeds to step S124. Otherwise, the process proceeds to step S121.

Step S124
The protocol processing unit 117 extracts received data from the received packet queue 113.

Step S125
Check the data destination. If the destination is a decode task, it notifies the decode task, and if it is a call control task, notifies the call control task. Proceed to step S121.

  Next, the operation of the wireless transmission task will be described with reference to the flowchart of FIG.

  In the present embodiment, the wireless transmission task performs the same processing for both the child device and the parent device. The transmission packet queue 111 exists for each destination MAC address, and the wireless transmission task performs the following processing for each transmission packet queue 111. However, in the following description, the operation will be described focusing on one transmission packet queue 111.

Step S131
The control unit 130 refers to the transmission packet queue 111 and determines whether the queue is empty. If it is empty, the process proceeds to step S131; otherwise, the process proceeds to step S132.

Step S132
The control unit 130 inquires of the wireless communication unit 107 whether transmission is possible. Specifically, the wireless communication unit 107 determines whether there is a radio wave having a frequency with which communication is currently performed, and confirms that no radio wave exists for a predetermined time with reference to the RTC 108. To do. If no radio wave is detected after the above-described time has elapsed, it is determined that transmission is possible, and the control unit 130 is notified that transmission is possible. In addition, when radio waves are detected within the above-described time, the control unit 130 is notified that transmission is impossible. If transmission is possible, the process proceeds to step S133, and if transmission is impossible, the process proceeds to step S131.

Step S133
The control unit 130 pays attention to the first entry in the transmission packet queue 111.

Step S134
The control unit 130 inquires of the error rate determination unit 119 whether the error rate is lower than a preset threshold. The error rate determination unit 119 passes the determination result to the control unit 130. From the received determination result, if the error rate is low, the process proceeds to step S143; otherwise, the process proceeds to step S135.

  Here, the description is continued assuming that the error rate is high.

Step S135
The control unit 130 refers to the transmission packet queue 111 and determines whether the number of entries is greater than one. If it is greater than 1, go to step S136, otherwise go to step S131.

Step S136
The control unit 130 extracts the data of the entry of interest from the transmission packet queue 111.

Step S137
The control unit 130 instructs the payload integration unit 112 to merge the data extracted in step S136. Details will be described later. Data to be transmitted is written in the transmission buffer 105.

Step S138
The control unit 130 pays attention to the next entry.

Step S139
The control unit 130 copies the data of the entry under attention. Here, only the data is copied without taking out the entry from the transmission packet queue 111.

Step S140
The control unit 130 instructs the payload integration unit 112 to merge the data copied in step S139 or the data extracted in step S143. Details will be described later. Data to be transmitted is written in the transmission buffer 105.

Step S141
Here, it is assumed that the radio frame is encrypted by an encryption method defined by IEEE 802.11i. The control unit 130 instructs the wireless communication unit 107 to add the CCMP header and the MIC key. Then, the wireless communication unit 107 calculates the CCMP header and the MIC key according to the encryption algorithm, and adds the CCMP header and the MIC key to the payload position defined by IEEE802.11i in the transmission buffer 105.

Step S142
The control unit 130 instructs the wireless communication unit 107 to transmit the contents of the transmission buffer 105. Then, the wireless communication unit 107 releases the instructed content as a wireless frame into the air. Proceed to step S131.

  In this way, two voice packet packets are combined into one radio frame. If it is determined in step S134 that the error rate is low, the process is as follows.

Step S143
Processing similar to that in step S136 is performed. The flow proceeds to step S140. In this case, as in a conventional wireless LAN, the packet is transmitted as it is as one wireless frame.

  Next, the details of the merge process will be described with reference to the flowchart of FIG.

  Here, it is assumed that data to be transmitted by the control unit 130 is passed to the payload integration unit 112.

Step S151
The payload integration unit 112 determines whether data is written in the transmission buffer 105. If it has been written, the process proceeds to step S157; otherwise, the process proceeds to step S152.

Step S152
The payload integration unit 112 writes the MAC header in the transmission buffer 105.

Step S153
The payload integration unit 112 passes the contents of the entry to the upper protocol analysis unit 118. Then, the upper layer protocol analysis unit 118 recognizes the protocol header of the upper layer protocol (here, LLC, IP, UDP, RTP) in the packet and stores the header of each layer. If the previous upper protocol header has already been stored, it is overwritten.

Step S154
The payload integration unit 112 calculates the total number of bytes of the received voice packet. Here, LLC header (8 bytes) + IPv6 header (40 bytes) + UDP header (8 bytes) + RTP header (12 bytes) + voice (80 bytes) = 148 bytes.

Step S155
The payload integration unit 112 writes the total number of bytes obtained in step S154 as the payload delimiter 1 in the transmission buffer 105. Here, 148 is written.

Step S156
The payload integration unit 112 writes the data received as a voice packet in the transmission buffer 105. End the merge process.

Step S157
The payload integration unit 112 passes the contents of the entry to the upper protocol analysis unit 118. Then, the upper layer protocol analysis unit 118 recognizes the protocol header of the upper layer protocol (here, LLC, IP, UDP, RTP) in the packet and compares it with the content stored in step S153. The upper protocol analysis unit 118 passes the result of analyzing the header to the payload integration unit 112. Here, the payload integration unit 112 is informed that the LLC header, IP header, and UDP header are redundant.

Step S158
The payload integrating unit 112 calculates the total number of bytes of data to be transmitted if a redundant header is omitted. Here, a total 93 of a 1-byte flag indicating which redundant header is included, a 12-byte RTP header that cannot be omitted, and 80-byte audio data is calculated.

Step S159
The payload integration unit 112 writes the value calculated in step S158 in the transmission buffer 105 as a payload delimiter. Here, 93 is written.

Step S160
Next, the payload integration unit 112 writes a flag 1 byte indicating which redundant header is in the transmission buffer 105. Here, the flag represents the second layer, the third layer, the fourth layer, and the fifth to seventh layers in accordance with the OSI layer model with 2 bits each, and 00 is “there was no corresponding header originally.” , 01 represents “there was a header but it was omitted because it was redundant” and 10 “it could not be omitted”. Here, since the LLC header, IP header, and UDP header can be omitted, and the RTP header cannot be omitted, the value of the flag is 01011010.

Step S161
The payload integration unit 112 writes the header and audio data that could not be omitted to the transmission buffer 105. End the merge process.

  Here, 12 bytes of RTP header and 80 bytes of audio data are subsequently written in the transmission buffer 105.

  FIG. 15 shows a case where only one voice packet is transmitted using the wireless frame format of IEEE 802.11 as a comparison with the present embodiment. FIG. 16 shows a radio frame format when two voice packets are combined into one radio frame according to this embodiment.

  First, after the CCMP header is written by the encryption engine built in the wireless communication unit 107 and the MIC key is added, the PLCP preamble, the PLCP header, and the FCS are added when the wireless communication unit 107 generates a wireless frame. . From the comparison between FIG. 15 and FIG. 16, if the two voice packets are not originally transmitted in two radio frames but are combined into one radio frame, the frame length is only 25% larger, which greatly reduces transmission efficiency. It can be seen that redundant voice packets can be transmitted. As a result, even if one of the midway radio frames is lost due to an error, the lost radio packet is included in the preceding and succeeding radio frames. Can be restored.

  Next, the operation of the wireless reception task will be described with reference to the flowchart of FIG.

  Here, it is assumed that the wireless frame addressed to the local station is received by the wireless communication unit 107, and the content of the frame is written as data in the reception buffer 104 in a state where the encryption is released. That is, it is assumed that the CCMP header and the MIC key are removed. Here, it is assumed that the wireless communication unit ignores the frames other than the wireless frame addressed to the own station. That is, data written to the reception buffer is limited to data destined for the own station.

Step S171
The payload dividing unit 114 refers to the reception buffer 104 to determine whether data is received. If received, the process proceeds to step S172; otherwise, the process proceeds to step S171.

Step S172
The payload dividing unit 114 extracts data from the reception buffer 104.

Step S173
The payload dividing unit 114 takes out the MAC header.

Step S174
Payload divider 114 focuses on the first payload.

Step S175
The payload dividing unit 114 interprets the next 1 byte as a delimiter, reads a value, obtains how many bytes the payload is, and cuts out the payload by the number of bytes.

Step S176
The payload dividing unit 114 passes the payload obtained in step S175 to the upper protocol analyzing unit 118. Then, the upper layer protocol analysis unit 118 interprets the headers in the second layer, the third layer, the fourth layer, and the fifth to seventh layers, and notifies the payload division unit 114 of them. Here, it is assumed that it can be interpreted as an LLC header, an IP header, a UDP header, and an RTP header. The upper protocol analysis unit 118 stores a header for each layer.

Step S177
The payload dividing unit 114 puts the obtained payload in the reception packet queue 113.

Step S178
The payload dividing unit 114 refers to the reception buffer 104 and determines whether all the payloads have been cut out. If all the payloads have been cut out, the process proceeds to step S171. Otherwise, the process proceeds to step S179.

Step S179
The payload dividing unit 114 refers to the reception buffer 104 and pays attention to the next payload.

Step S180
The payload dividing unit 114 interprets the next one byte in the reception buffer 104 as a delimiter, reads the value, obtains the number of the payload of interest, and cuts it out as many as the number of bytes.

Step S181
The payload dividing unit 114 interprets the next 1 byte as an omission flag and determines which layer's header is omitted. Further, for the omitted header, the higher-level protocol analysis unit 118 is instructed to restore the header from the contents of the header stored in step S176. Then, the upper layer protocol analysis unit 118 compares the payload and the content stored in step S176, and restores the header of each layer. Here, since a checksum is included in the IP header and the UDP header, the checksum is calculated from the contents of the payload and restored as a header. Thus, the entire voice packet before the header is omitted is restored. Proceed to step S177.

  Here, assuming that the value of the flag is 01011010, the flag represents the second layer, the third layer, the fourth layer, and the fifth to seventh layers by 2 bits according to the OSI layer model. 00 represents “there was no corresponding header originally”, 01 represents “there was a header but was omitted because it was redundant”, and 10 “it could not be omitted”, so the LLC header was omitted, the IP header was omitted, and the UDP header, respectively. It can be interpreted as omission, no omission of the RTP header. Therefore, the portion after the flag of interest is interpreted as an RTP header, and the omitted header is restored based on the content stored in step S176. Further, the checksum is recalculated for the IP header and the UDP header, and the header is restored.

  Through the above processing, even though two voice packets are originally combined into one radio frame, they are correctly divided into the original voice packets and passed to the protocol processing unit 117.

  Here, when communication is normally performed, two identical voice packets are received. However, in the RTP protocol, as shown in the description of the decode task described above, the decode task includes a time stamp in the RTP header. There is no problem because unnecessary packets are discarded while only the necessary packets are decoded and reproduced as audio.

  Next, the task of the master unit will be described. However, since the wireless reception task and the wireless transmission task are the same as the slave unit, the description thereof is omitted.

  The bridge task process will be described with reference to the flowchart of FIG.

Step S191
The wired-wireless bridge unit 120 determines whether there is an entry in the reception packet queue 113. If there is an entry, the process proceeds to step S192. Otherwise, the process proceeds to step S195.

Step S192
The wired-wireless bridge unit 120 takes out an entry from the reception packet queue 113.

Step S193
The wired-wireless bridge unit 120 refers to the contents of the entry extracted in step S192 and determines whether it is necessary to relay to the LAN side (wired). In this determination, the destination of the OSI second layer is used. In this embodiment, the second layer is determined by the MAC address defined in IEEE 802.11. The address learning method for this determination is not related to the gist of the present invention, and is omitted. If relaying is necessary, the process proceeds to step S194. Otherwise, the process proceeds to step S191.

Step S194
The wired-wireless bridge unit 120 converts the IEEE 802.11 MAC header format into the IEEE 802.3 MAC header format, and transmits the entry contents from the LAN communication unit 106. The process proceeds to step S191.

Step S195
The wired-wireless bridge unit 120 inquires of the LAN communication unit 106 whether data is received from the wired LAN. If it has been received, the process proceeds to step S196. Otherwise, the process proceeds to step S191.

Step S196
The wired-wireless bridge unit 120 receives received data from the LAN communication unit 106.

Step S197
The wired-wireless bridge unit 120 determines whether it is necessary to relay the received data extracted in step S196 to the wireless LAN side. Since the method of determining whether to relay is the same as the conventional bridge processing, it is omitted. If it is necessary to relay, the process proceeds to step S198; otherwise, the process proceeds to step S191.

Step S198
The wired-wireless bridge unit 120 converts the received data extracted in step S 196 from the IEEE 802.3 MAC header format to the IEEE 802.11 MAC header format, and puts the received data in the transmission packet queue 111. The process proceeds to step S191.

  FIG. 19 shows how voice packets are transmitted in the present embodiment.

  In FIG. 19, voice packet 1 and voice packet 2 are sent together in radio frame A, voice packet 2 and voice packet 3 are sent together in radio frame B, and voice packet 3 and voice packet 4 are sent together in radio frame C. Has been.

  FIG. 20 shows a case where the radio frame B is lost due to a communication error. The receiving side can receive the voice packet 1, the voice packet 2, the voice packet 3, and the voice packet 4 by the radio frame A and the radio frame C. Therefore, there is no need to retransmit the radio frame B.

  As described above, conventionally, due to the occurrence of an error, retransmission is unavoidable, and the subsequent arrival time of the voice is delayed, and further, this delay accumulates, causing the receiving terminal side to overflow the jitter buffer. However, according to the first embodiment, since the voice packet is made redundant by the above configuration, even if an error occurs, it is not retransmitted. , The original voice can be restored.

  Moreover, since voice packets are collectively transmitted as a single radio frame, the bandwidth is not compressed more than necessary. Furthermore, since the voice packet is analyzed and unnecessary headers are omitted to be combined into one wireless frame, the data amount per frame can be reduced. As a result, a wireless LAN telephone user is provided with a high-quality telephone environment, and a user who performs data communication within the same wireless LAN does not press the bandwidth more than necessary. Can provide a good communication environment.

  In this embodiment, it is assumed that retransmission is not performed when an error occurs. However, even if the number of retransmissions is smaller than the conventional one, the gist of the present invention is not changed and sufficient effects are obtained. can get.

(Embodiment 2)
FIG. 21 is a functional block diagram of the slave unit in the second embodiment of the present invention.

  In FIG. 21, 101 is a call destination, an operation unit for instructing a call at the time of an incoming call, and an instruction for terminating a call, 102 is a voice input unit for inputting voice, and 103 outputs a voice. An audio output unit 104 for receiving data, a reception buffer for accumulating data extracted from the received radio frame, and a transmission buffer 105 for accumulating data for radio transmission.

  A wireless communication unit 107 transmits the data accumulated in the transmission buffer 105 as a wireless frame, receives a wireless frame, and stores the contents of the frame in the reception buffer 104. 108 measures the passage of time. The RTC 109 is a parameter storage unit that stores a voice delay allowable time, a voice codec period, a voice codec delay, and a network delay amount designated in advance.

  110 A / D converts the voice input from the voice input unit 102, converts (encodes) the voice into a voice packet using a predetermined algorithm, and decodes the voice data using a predetermined algorithm. A codec unit 111 that performs D / A conversion and outputs the audio packet encoded by the codec unit 110 to the audio output unit 103, a transmission packet that is stored in a FIFO manner together with a time when encoding of the audio packet is completed, that is, a transmission request reception time A queue 112 is a payload integration unit that writes packets input to the transmission packet queue 111 within one transmission waiting time into a single radio frame and writes the same into the transmission buffer.

  113 receives data received as a radio frame into packets and stores them in a FIFO manner. A reception packet queue 114 determines whether the content stored in the reception buffer 104 was originally one packet, In the case where the packets are integrated, this is a payload dividing unit that breaks down the packets into a plurality of packets and writes them into the received packet queue 113 by the FIFO method.

  115 refers to the audio delay allowable time, the audio codec period, the audio codec delay, and the network delay amount specified in advance, stored in the parameter storage unit 109, and sets the RTC 108 value as the transmission request reception time. And a transmission waiting time calculation unit that calculates a transmission waiting time.

  116 is a call control unit that controls outgoing / incoming calls, call connection / disconnection, and outputs a dial tone, busy tone, ringer, ring back tone according to the state of each call to the voice output unit 103 117 is a protocol processing unit that processes call setting and cancellation and voice packet transmission / reception during a call according to a designated protocol, 121 is a network delay measuring unit, and 130 is a network delay measuring unit. It is a control part to control.

  The correspondence between the configuration of FIG. 21 and the configuration of FIG. 2 will be described.

  The operation unit 101 is realized by a keyboard 211, the voice input unit 102 is realized by a microphone 208, and the voice output unit 103 is realized by a 210 speaker.

  104 reception buffers, 105 transmission buffers, 109 parameter storage units, 111 transmission packet queues, and 113 reception packet queues are realized by 203 RAMs.

  107 wireless communication units are 205 baseband and 206 RF, 108 RTCs are 204 RTCs, 110 codecs are 212 codecs, 207 A / Ds, 209 D / As, Each is realized.

  112 payload integration units, 114 payload division units, 115 transmission waiting time calculation units, 121 network delay measurement units, and 130 control units are stored in the ROM of 202 by the CPU of 201. The program is realized by referring to data stored in the ROM 202 or referring to or changing data stored in the RAM 203.

  FIG. 22 is a functional block diagram of the parent device in the second embodiment of the present invention.

  In FIG. 22, 104 is a reception buffer for accumulating data extracted from received radio frames, 105 is a transmission buffer for accumulating data for radio transmission, and 106 is a LAN communication unit for connecting to a wired network. 107 is a wireless communication unit that converts the data stored in the transmission buffer 105 into a wireless frame and transmits the data, and receives the wireless frame and stores the contents of the frame in the reception buffer 104.

  108 is an RTC for measuring the passage of time, and 111 is a wireless frame for transmitting an Ethernet (registered trademark) frame from the LAN side, which will be described later, that the wired-wireless bridge unit 120 determines that relaying is necessary. In addition, a transmission packet queue 112 that stores the transmission request reception time together with the reception time in a FIFO manner is a payload integration unit 112 that collects packets input to the transmission packet queue 111 within a transmission waiting time into one radio frame and writes them into the transmission buffer. is there.

  113 receives data received as a radio frame into packets and stores them in a FIFO manner. Receive packet queue 114 determines whether the content stored in the receive buffer 104 was originally one packet, and a plurality of packets Are integrated into a plurality of packets and written into the reception packet queue 113 by the FIFO method.

  Reference numeral 120 denotes a wired-wireless bridge unit that relays a frame between wired and wireless if necessary, and discards the frame otherwise. Reference numeral 130 denotes a control unit that controls the whole.

  The correspondence between the configuration of FIG. 22 and the configuration of FIG. 4 will be described.

  The 104 reception buffer, 105 transmission buffer, 111 transmission packet queue, and 113 reception packet queue are realized by 203 RAMs.

  The wireless communication unit 107 is realized by 205 baseband and 206 RF, the RTC 108 is realized by 204 RTC, and the LAN communication unit 106 is realized by 213 network I / F.

  The payload integration unit 112, the payload division unit 114, the wired-wireless bridge unit 120, and the control unit 130 store programs stored in the ROM 202 of the CPU 201 in the ROM 202. This is realized by referring to the data stored in the memory, or referring to or changing the data stored in the RAM 203.

  The overall configuration of the wireless LAN telephone system and the operation outline of the parent device and the child device are not different from those of the first embodiment, and thus description thereof is omitted.

  First, the operation of the slave unit will be described.

  FIG. 23 shows a task configuration of the slave unit. Compared to FIG. 7, a measurement task is newly added. On the other hand, the task configuration of the parent device is the same as that of the first embodiment (FIG. 8).

Next, the operation of the task of the slave unit will be described. Of the tasks of the slave unit, the encoding task, decoding task, and call control task are the same as those in the first embodiment, and thus description thereof is omitted.

Here, the measurement task which is different from the first embodiment will be described according to the flowchart of FIG.

  In the present embodiment, it is premised that the slave units that are making a call match each other's RTC 108 in advance by another method. As a method for adjusting the clocks of each other, a method using GPS and a method using a protocol called NTP are common, but details are not described here.

Step S211
The network delay measurement unit 121 refers to the reception packet queue 113 to determine whether or not the measurement packet has arrived. If it has arrived, the process proceeds to step S212. Otherwise, the process proceeds to S214.

Step S212
The network delay measurement unit 121 extracts a packet from the reception packet queue 113.

Step S213
The network delay measurement unit 121 refers to the contents of the extracted packet, reads when the packet is transmitted, refers to the RTC 108, and compares it with the current time. The result is written in the parameter storage unit 109 as a network delay amount. The process proceeds to step S211. Here, it is assumed that the time written in the packet is 12:33 12.654 223. If the RTC 108 currently indicates 12:33 12.734 223, the time difference is 80 ms, and this is written in the parameter storage unit 109 as a network delay amount. The process proceeds to step S211.

Step S214
The network delay measurement unit 121 refers to the RTC 108 to determine whether the scheduled transmission time has come. If the scheduled time is reached, the next scheduled transmission time is set, and the process proceeds to step S215. Otherwise, the process proceeds to step S211. Here, the measurement packet is transmitted once every 5 seconds. Therefore, if the current value of the RTC 108 is 12:33 17.255 109, the scheduled transmission time is 12:33 22.255 109 after 5 seconds.

Step S215
The network delay measuring unit 121 refers to the RTC 108, reads the current time 12:33 17.255 109, and puts this in the transmission packet queue 111 as the contents of the packet. The process proceeds to step S211.

  In this way, the slave units exchange measurement packets with each other to measure the amount of delay in the network, and based on this, determine how many voice packets should be combined into one radio frame based on the wireless transmission task. (Details will be described later). As a result, even if the network traffic fluctuates and the network delay amount changes, the voice packet can be made redundant within the range of the voice delay allowable time, so that a stable call can be secured.

  FIG. 25 is a flowchart of the wireless transmission task of the child device in the second embodiment of the present invention. The transmission packet queue 111 exists for each destination MAC address, and the wireless transmission task performs the following processing for each transmission packet queue 111. However, in the following description, the operation will be described focusing on one transmission packet queue 111.

Steps S221 to S223
The same processing as steps S131 to S133 of FIG. 13 in the first embodiment is performed.

Step S224
The control unit 130 requests the transmission waiting allowable time calculating unit 115 to calculate the transmission waiting allowable time for the entry of interest. Then, the allowable transmission waiting time calculation unit 115 refers to the parameter storage unit 109, the RTC 108, and the transmission request reception time recorded in association with the entry, and calculates the allowable delay time. First, a transmission waiting time (how much time has elapsed since the transmission request was accepted) is obtained from the RTC 108 and the transmission request acceptance time of the entry of interest. Here, the following values are assumed.

RTC = 12: 33 22.043 994
Transmission request reception time = 12: 33 22.08 876
Therefore, transmission waiting time = RTC−transmission request reception time = 35 ms.
In addition, the following values:
Codec period = 10 ms
Codec delay = 1 ms
Network delay = 80ms
Codec waiting time = 10 ms
Total delay allowable time = 120 ms
Is stored in the parameter storage unit 109 in advance. Note that codec delay means that A / D conversion is performed after audio is input, and data encoded by a specified algorithm (in this case, μ-law PCM 8 kHz 8-bit sampling is specified) is output. It is a time until the data frame is received, and it is possible to obtain a voice frame only after collecting this data corresponding to the codec period. In addition, the delay time from when the audio frame is decoded and D / A converted and output as audio is also set to the same value. Although this delay time may be asymmetric depending on the codec algorithm, it will be described here as being symmetric. Furthermore, the codec waiting time is the time required to provide a jitter buffer on the receiving side, temporarily store audio packets waiting for decoding, and prevent the audio from being interrupted even if the arrival of packets fluctuates. is there. It is assumed that the network delay is regularly updated by the above measurement task. The transmission waiting allowable time is calculated by the above value and the following equation.

Allowable transmission wait time = Allowable total delay time-Codec period-Codec delay x 2
-Network delay-Codec waiting time-Transmission waiting time FIG. 26 illustrates the above equation in an easy-to-understand manner.

  The allowable transmission waiting time of the entry focused on from the above equation is -17 ms. Here, the negative value indicates that the voice does not arrive within the allowable time even if it is transmitted from now.

  The transmission waiting allowable time calculation unit 115 notifies the control unit 130 that “transmission waiting allowable time is −17 ms”.

Step S225
If the transmission waiting allowable time received by the control unit 130 from the transmission waiting allowable time calculating unit 115 shows a negative value, that is, if it is not in time even if it is transmitted from now, go to step S226, otherwise step S229. Proceed to Here, since the negative value is shown, it progresses to step S226.

Step S226
The control unit 130 extracts the data of the entry of interest from the transmission packet queue 111.

  In the above example, it is determined that the entry of interest is not in time even if it is transmitted from now on, and is discarded.

Step S227
The control unit 130 refers to the transmission packet queue 111 and determines whether there is an entry next to the entry of interest. If it exists, the process proceeds to step S227; otherwise, the process proceeds to step S221. Here, as shown in FIG. 27, the description will be continued assuming that an entry exists.

Step S228
The control unit 130 pays attention to the next entry. Proceed to step S224.

  As described above, by repeating the processing of steps S224 to S228, voice packets that do not arrive at the other party within the allowable time even if transmitted are discarded. In the example so far, entries 1 and 2 in FIG. 27 are discarded.

  Next, a case will be described in which it is determined in step S225 that it will arrive at the other party within an allowable time after transmission from now. Since entry 3 is determined to arrive within the allowable time, the process proceeds to step S229.

Step S229
The control unit 130 copies the contents of the entry under attention. Here, the contents of entry 3 are temporarily stored by control unit 130.

Step S230
The control unit 130 instructs the payload integration unit 112 to merge the data copied in step S229. Details will be described later. Data to be transmitted is written in the transmission buffer 105.

Step S231
The control unit 130 refers to the transmission packet queue 111 and determines whether there is an entry next to the entry of interest. If it exists, the process proceeds to step S232; otherwise, the process proceeds to step S233.

  By repeating steps S229 to S232, the contents of the entries in the transmission packet queue are merged until there are no more entries.

Step S232
The control unit 130 pays attention to the next entry. Proceed to step S229.

Step S233
After the data up to the entry 5 are merged, there is no more entry to be merged in the packet transmission queue 11, so step S233 is executed.

  Here, it is assumed that the radio frame is encrypted by an encryption method defined by IEEE 802.11i. The control unit 130 instructs the wireless communication unit 107 to add the CCMP header and the MIC key. Then, the wireless communication unit 107 calculates the CCMP header and the MIC key according to the encryption algorithm, and adds the CCMP header and the MIC key to the payload position defined by IEEE802.11i in the transmission buffer 105.

Step S234
The control unit 130 instructs the wireless communication unit 107 to transmit the contents of the transmission buffer 105. Then, the wireless communication unit 107 releases the instructed content as a wireless frame into the air. Proceed to step S221.

  Here, it is assumed that the preamble and FCS defined in IEEE 802.11 are added by the wireless communication unit 107.

  Next, data merge processing will be described with reference to the flowchart of FIG. Compared with the first embodiment, in this embodiment, payloads are simply combined into one radio frame without performing upper protocol analysis processing.

Step S241
The payload integration unit 112 determines whether data is written in the transmission buffer 105. If it has been written, the process proceeds to step S244; otherwise, the process proceeds to step S242.

Step S242
The payload integration unit 112 writes the MAC header in the transmission buffer 105. The process proceeds to step S244.

Step S243
The payload integration unit 112 calculates the total number of bytes of the received voice packet. Here, LLC header (8 bytes) + IPv6 header (40 bytes) + UDP header (8 bytes) + RTP header (12 bytes) + voice (80 bytes) = 148 bytes.

Step S244
The payload integration unit 112 writes the total number of bytes obtained in step S243 in the transmission buffer 105 as a payload delimiter. Here, 148 is written.

Step S245
The payload integration unit 112 writes the data received as a voice packet in the transmission buffer 105. End the merge process.

  FIG. 29 shows the state of the transmission buffer 105 written as described above. In the examples so far, entries 3 to 5 in FIG. 27 are written as payloads 1 to 3.

  Next, the operation of the wireless reception task will be described with reference to the flowchart of FIG.

  In the present embodiment, the wireless reception task performs the same processing for both the child device and the parent device. Here, it is assumed that the radio frame addressed to the own station is received by the radio communication unit 107 and the contents of the frame are written in the reception buffer 104 as data.

Steps S251 to S254
This is the same as steps S171 to S174 in FIG. 17 in the first embodiment.

Step S255
The payload dividing unit 114 interprets the first byte as a delimiter, reads a value, obtains how many bytes the payload is, and takes out subsequent payloads. Proceed to step S257.

Steps S256 to S259
This is the same as steps S177 to S180 in FIG. 17 in the first embodiment.

  By the above processing, even if a plurality of voice packets are originally combined into one radio frame, they are correctly divided into the original voice packets and passed to the protocol processing unit 117. The decoding task completes the decoding process within a specified delay time and reproduces it as sound.

  Next, regarding the parent device, the task configuration of the parent device is the same as that of the first embodiment, and the bridge task is the same as that of the first embodiment. Since the wireless reception task is the same as that of the child device of the second embodiment, the description thereof is omitted, and only the wireless transmission task of the parent device is described here.

  The radio transmission task of the master unit in this embodiment will be described with reference to the flowchart of FIG.

Steps S261 to S262
The same processing as that in steps S221 to S222 in FIG.

Step S263
The same processing as that in step S223 in FIG. The process proceeds to step S264.

Step S264
The same processing as that in step S226 in FIG. Proceed to step S265.

Steps S265 to S269
The same processing as that in steps S230 to S233 in FIG.

Step S269
The same processing as that in step S234 in FIG. Proceed to step S261.

  As explained so far, if the slave unit and the master unit shown in this embodiment are used in combination, even if an error occurs while keeping the voice delay during a call within a practical range, It can provide high call quality with no sound interruption.

  As described above, conventionally, due to the occurrence of an error, retransmission has occurred, and accordingly, the arrival time of the subsequent voice is delayed, and further, this delay accumulates, causing the receiving terminal side to overflow the jitter buffer, Although quality degradation such as voice interruption has been caused, according to the present embodiment, voice packets are redundantly transmitted by the above configuration, so that the original voice is restored even if an error occurs. be able to.

  Moreover, since voice packets are collectively transmitted as a single radio frame, the bandwidth is not compressed more than necessary. Furthermore, even if the network traffic fluctuates, the delay time of the network can be measured, and the transmission timing and the amount of packet superposition per frame can be adapted to this. As a result, a wireless LAN telephone user is provided with a high-quality telephone environment, and a user who performs data communication within the same wireless LAN does not press the bandwidth more than necessary. Can provide a good communication environment.

(Embodiment 3)
FIG. 32 is a functional block diagram of a slave unit in the third embodiment of the present invention.

  In FIG. 32, 101 designates a call destination, an operation unit for instructing a call at the time of an incoming call, and an instruction for terminating a call, 102 a voice input unit for inputting voice, and 103 outputting voice. An audio output unit 104 for receiving data, a reception buffer for accumulating data extracted from the received radio frame, and a transmission buffer 105 for accumulating data for radio transmission.

  107 is a wireless communication unit that converts the data accumulated in the transmission buffer 105 into a radio frame and transmits it, and receives a radio frame and stores the contents of the frame in the reception buffer 104. The RTC 109 is a parameter storage unit that stores a voice delay allowable time, a voice codec period, a voice codec delay, and a network delay amount designated in advance.

  110 performs A / D conversion on the voice input from the voice input unit 102 and converts (encodes) the voice into a voice packet using a predetermined algorithm, and decodes the voice data using a predetermined algorithm. A codec unit 111 that performs A / A conversion and outputs the result to the audio output unit 103, a transmission packet queue that stores the audio packet encoded by the codec unit 110 in a FIFO manner together with a time when encoding is completed, that is, a transmission request reception time It is.

  112 is a payload integration unit that writes packets that are input to the transmission packet queue 111 within one transmission frame into a single radio frame and writes them in the transmission buffer. 113 is a FIFO that decomposes data received as radio frames into packets. This is a received packet queue that is stored in a manner.

114 determines whether or not the content stored in the reception buffer 104 was originally one packet. If a plurality of packets are integrated, the packet is decomposed into a plurality of packets, and the received packet queue 113 receives the FIFO. Payload division unit,
115 refers to the audio delay allowable time, the audio codec period, the audio codec delay, and the network delay amount specified in advance stored in the parameter storage unit 109, and sets the RTC 108 value as the transmission request reception time. And a transmission waiting time calculation unit that calculates a transmission waiting time.

  116 is a call control unit that controls outgoing / incoming calls, call connection / disconnection, and outputs a dial tone, busy tone, ringer, ring back tone according to the state of each call to the voice output unit 103 Reference numeral 117 denotes a protocol processing unit that processes call setting and cancellation and voice packet transmission / reception during a call according to a designated protocol.

  Reference numeral 122 denotes a reception history buffer that stores the contents or identifiers of a predetermined number of voice packets in the FIFO method, and 123 refers to the reception history buffer 122 to store the same voice packet as the designated voice packet. The duplicate packet search unit 130 for searching whether or not there is a control unit that controls the whole.

  Here, the correspondence between the configuration of FIG. 32 and the configuration of FIG. 2 will be described.

  The operation unit 101 is realized by a keyboard 211, the voice input unit 102 is realized by a microphone 208, and the voice output unit 103 is realized by a 210 speaker.

  The 104 reception buffer, 105 transmission buffer, 109 parameter storage unit, 111 transmission packet queue, 113 reception packet queue, and 122 reception history buffer are realized by 203 RAMs.

  107 wireless communication units are realized by 205 baseband and 206 RF, 108 RTCs are realized by 204 RTCs, 110 codec units are realized by 212 codecs, 207 A / D, and 209 D / A. Has been.

  112 payload integration unit, 114 payload division unit, 115 transmission waiting time calculation unit, 123 duplicate packet search unit, and 130 control unit are stored in the ROM of 202 by the CPU of 201. The program is implemented by referring to the data stored in the ROM 202 and referring to or changing the data stored in the RAM 203.

  FIG. 33 is a functional block diagram of the parent device in the third embodiment of the present invention.

  In FIG. 33, 104 is a reception buffer for accumulating data extracted from a received radio frame, 105 is a transmission buffer for accumulating data for radio transmission, and 106 is a LAN communication unit for connecting to a wired network. It is.

  107 is a wireless communication unit that converts the data accumulated in the transmission buffer 105 into a radio frame and transmits it, and receives a radio frame and stores the contents of the frame in the reception buffer 104. The RTC 111 stores the Ethernet request (registered trademark) frame from the LAN side, which will be described later, as a wireless frame by the wired-to-wireless bridge unit 120, which will be described later, and stores it in the FIFO format together with the transmission request reception time. This is a transmission packet queue.

  112 is a payload integration unit that writes packets that are input to the transmission packet queue 111 within one transmission frame into a single radio frame and writes them in the transmission buffer. 113 is a FIFO that decomposes data received as radio frames into packets. The received packet queue 114, which is stored by the method, determines whether or not the content stored in the reception buffer 104 was originally one packet, and if a plurality of packets are integrated, it is decomposed into a plurality of packets. , A payload division unit that writes data to the reception packet queue 113 using the FIFO method.

  120 is a relay between wired and wireless frames if necessary, and is otherwise discarded. A wired-wireless bridge unit 122 stores the contents or identifiers of a predetermined number of voice packets in the FIFO method. The reception history buffer 123, which searches for whether or not the same voice packet as the designated voice packet is stored with reference to the reception history buffer 122, a duplicate packet search unit 130 controls the whole Part.

  Here, the correspondence between the configuration of FIG. 33 and the configuration of FIG. 4 will be described.

  104 reception buffers, 105 transmission buffers, 111 transmission packet queues, 113 reception packet queues, and 122 reception history buffers are realized by 203 RAMs.

  The wireless communication unit 107 is realized by 205 baseband and 206 RF, the RTC 108 is realized by 204 RTC, and the LAN communication unit 106 is realized by 213 network I / F.

  112 payload integration unit, 114 payload division unit, 120 wired-wireless bridge unit, 123 duplicate packet search unit, and 130 control unit are programs stored in ROM 202 by CPU 201 Is realized by referring to data stored in the ROM 202 or referring to or changing data stored in the RAM 203.

  In the present embodiment, the overall configuration of the wireless LAN telephone system and the operation outline of the parent device and the child device are the same as those in the first embodiment, and thus the description thereof is omitted. Similarly, the task configuration of the parent device and the child device is the same as that of the first embodiment, and thus the description thereof is omitted.

  FIG. 34 is a flowchart of the wireless transmission task of the child device in the present embodiment.

  The transmission packet queue 111 exists for each destination MAC address, and the wireless transmission task performs the following processing for each transmission packet queue 111. However, in the following description, the operation will be described focusing on one transmission packet queue 111. The present embodiment is very similar to the second embodiment, but in the second embodiment, all the packets that can be transmitted within the allowable time are merged and transmitted, whereas in this embodiment, the oldest packet that can be transmitted within the allowable time is transmitted. The difference is that only the most recent one is merged. Hereinafter, this point will be described in detail.

Steps S301 to S308
The same processing as steps S221 to S228 of FIG. 25 in the second embodiment is performed.

  Packets that do not arrive within the allowable time even if they are transmitted from now on in the processing so far are deleted from the transmission packet queue 111.

Step S309
The control unit 130 refers to the transmission packet queue 111 and determines whether there is an entry next to the entry of interest. If it exists, the process proceeds to step S314; otherwise, the process proceeds to step S310. Here, the description is continued assuming that no entry exists. In this case, only one voice packet remains in the transmission packet queue 111.

Step S310
The control unit 130 copies the contents of the entry under attention.

Step S311
The control unit 130 instructs the payload integration unit 112 to merge the data copied in step S310. Details will be described later. Data to be transmitted is written in the transmission buffer 105.

Step S312
Here, it is assumed that the radio frame is encrypted by an encryption method defined by IEEE 802.11i. The control unit 130 instructs the wireless communication unit 107 to add the CCMP header and the MIC key. Then, the wireless communication unit 107 calculates the CCMP header and the MIC key according to the encryption algorithm, and adds the CCMP header and the MIC key to the payload position defined by IEEE802.11i in the transmission buffer 105.

Step S313
The control unit 130 instructs the wireless communication unit 107 to transmit the contents of the transmission buffer 105. Then, the wireless communication unit 107 releases the instructed content as a wireless frame into the air. Here, it is assumed that the preamble and FCS defined in IEEE 802.11 are added by the wireless communication unit 107.

  Proceed to step S301.

  Next, a case where the next entry exists in step S309 will be described.

  Assume that five entries are registered in the transmission packet queue 111 as shown in FIG. In the processing up to step S309, entries 1 and 2 are discarded because they do not arrive within the allowable time even if they are transmitted from now. That is, attention is currently focused on entry 3. Since entry 4 exists in the transmission packet queue 111, step S314 is executed.

Step S314
The same processing as in step S310 is performed.

Step S315
The same processing as that in step S311 is performed.

Step S316
The same process as in step S308 is performed.

Step S317
The same processing as in step S309 is performed. If the next entry exists, the process proceeds to step S316; otherwise, the process proceeds to step S310.

  In this way, the oldest voice packet is merged as transmission data in the processes of steps S314 and S315. Furthermore, the newest packet is found in the transmission packet queue 111 through steps S316 and S317.

  Thereafter, the oldest packet and the newest packet are merged and transmitted by the processing in steps S310 to S313. In the present embodiment, it is assumed that the same merge process as in the second embodiment is performed.

  Next, the operation of the wireless reception task will be described with reference to the flowchart of FIG.

  In this embodiment, the wireless reception task performs the same processing for both the slave unit and the master unit. Here, it is assumed that the radio frame addressed to the own station is received by the radio communication unit 107 and the contents of the frame are written in the reception buffer 104 as data.

Steps S321 to S325
The same processing as steps S251 to S255 of FIG. 30 in the second embodiment is performed.

Step S326
The payload dividing unit 114 inquires of the duplicate packet searching unit 123 whether or not a packet having the same content as the currently focused payload is already registered in the reception history buffer 122.

Step S327
The duplicate packet search unit 123 notifies the control unit 130 of the result of step S326. Details of this processing will be described later. If registered, the process proceeds to step S328; otherwise, the process proceeds to step S331.

Steps S328 to S329
The same processing as steps S257 to S258 of FIG. 30 in the second embodiment is performed.

Step S330
The same process as step S259 of FIG. 30 in the second embodiment is performed. The process proceeds to step S326.

Step S331
The payload dividing unit 114 puts the obtained payload in the reception packet queue 113. Proceed to step S328.

  By the above processing, even if a plurality of voice packets are originally combined into one radio frame, they are correctly divided into the original voice packets and passed to the protocol processing unit 117. Even if the same voice packet is copied by the transmission side and transmitted in different radio frames, the same voice packet is discarded by this process. As a result, the base unit does not send the same voice packet to the LAN, so that the network traffic is not increased unnecessarily.

  Next, details of the above-described duplicate packet search process will be described.

  FIG. 36 is a flowchart showing duplicate packet search processing in the present embodiment.

  Here, it is assumed that voice packets are transmitted by the RTP protocol. In the RTP protocol, a sequence number is written in the header portion, and it is possible to detect duplication or omission of voice packets, change of order, and the like. Here, it is assumed that the reception history buffer 122 stores ten sequence numbers by the FIFO method.

Step S341
The duplicate packet search unit 123 determines whether or not a sequence number is registered in the reception history buffer 122. If none is registered, the processing ends as “no duplication”. Otherwise, the process proceeds to step S342.

Step S342
The duplicate packet search unit 123 pays attention to the first sequence number stored in the FIFO method in the reception history buffer 122.

Step S343
The duplicate packet search unit 123 refers to the sequence number in the header part of the RTP packet included in the payload specified by the payload dividing unit 114, and checks whether or not it matches the currently focused sequence number. If they match, the process ends as “duplicate”. Otherwise, the process proceeds to step S344.

Step S344
The duplicate packet search unit 123 determines whether or not a sequence number is stored in the reception history buffer 122 next to the sequence number of interest. If stored, the process proceeds to step S345. Otherwise, the processing ends as “no duplication”.

Step S345
The duplicate packet search unit 123 moves the sequence number currently being noted to the next sequence number stored in the reception history buffer 122 by the FIFO method. The process proceeds to step S343.

  With the above processing, in the present embodiment, the sequence number of the RTP header of the received voice packet is checked over the past 10 packets to determine whether or not it has already been received. As a result, what has already been received is processed as “duplicate”, and is discarded by the processing of the payload integration unit 114.

  Next, regarding the parent device, the task configuration of the parent device is the same as that of the first embodiment. Here, only the wireless transmission task of the parent device different from the first and second embodiments will be described.

  The wireless transmission task of the master unit in this embodiment will be described with reference to the flowchart of FIG.

Steps S351 to S352
The same processing as in steps S131 to S132 of FIG. 13 in the first embodiment is performed.

Step S353
The same process as step S133 of FIG. 13 in the first embodiment is performed. Proceed to step S354.

Step S354
The control unit 130 refers to the transmission packet queue 111 and determines whether the number of entries is greater than one. If greater than 1, the process proceeds to step S355; otherwise, the process proceeds to step S358.

Steps S355 to S361
The same processing as steps S136 to S142 of FIG. 13 in the first embodiment is performed. The process proceeds to step S351.

  As described above, if the slave unit and the master unit described in this embodiment are used in combination, burst errors that tend to occur in a wireless LAN occur, and continuous radio frames are considered transmission errors. Even if this happens, voice packet loss does not occur. For example, voice packets 1 and 3 for radio frame A, voice packets 2 and 4 for radio frame B, voice packets 3 and 5 for radio frame C, voice packets 4 and 6 for radio frame D, and voice packet 5 for radio frame E 7. When audio packets 6 and 8 are merged and transmitted in the radio frame F, the audio included in the radio frames C and D is lost even if the radio frames C and D in the middle are continuously lost due to a burst error. Packets 3, 5, 4, and 6 are included in radio frame A, radio frame E, radio frame B, and radio frame F, respectively, so that the receiving side can use this to restore the original voice. It becomes. Also, unlike the method shown in the second embodiment, since only two voice packets are carried per frame, the length of the radio frame is not increased more than necessary, and communication is performed using the same channel. The influence on other terminals that are present can be further reduced.

  As described above, conventionally, due to the occurrence of an error, retransmission has occurred, and accordingly, the arrival time of the subsequent voice is delayed, and further, this delay accumulates, causing the receiving terminal side to overflow the jitter buffer, Although quality degradation such as voice interruption has been caused, according to the third embodiment, voice packets are redundantly transmitted by the above configuration, so that the original voice is restored even if an error occurs. be able to. Moreover, since voice packets are collectively transmitted as a single radio frame, the bandwidth is not compressed more than necessary. Furthermore, even if transmission / reception of radio frames fails continuously due to a burst error, it is possible to avoid the loss of voice packets as much as possible by interleaving the voice packets. In addition, by discarding the same voice packet on the receiving side, there is no need to worry about placing more load on the network than necessary. As a result, a wireless LAN telephone user is provided with a high-quality telephone environment, and a user who performs data communication within the same wireless LAN does not press the bandwidth more than necessary. Can provide a good communication environment.

  In this embodiment, two voice packets are transmitted as one radio frame. However, three or more voice packets are selected by a predetermined algorithm and transmitted as one radio frame. Even so, there is no difference from the gist of the present invention.

  The wireless LAN telephone communication method and system according to the present invention can be used for, for example, a cordless telephone using a wireless LAN because it avoids the influence of errors in wireless communication and can provide high call quality.

Functional block diagram of slave unit in the first embodiment of the present invention The circuit block diagram of the subunit | mobile_unit in Embodiment 1 of this invention Functional block diagram of base unit in Embodiment 1 of the present invention Circuit block diagram of base unit in Embodiment 1 of the present invention 1 is an overall configuration diagram of a system according to Embodiment 1 of the present invention. The sequence diagram which showed the flow of the whole process in Embodiment 1 of this invention The task block diagram of the subunit | mobile_unit in Embodiment 1 of this invention Task configuration diagram of base unit in Embodiment 1 of the present invention Flowchart of slave device encoding task in the first embodiment of the present invention Flowchart of slave unit decoding task in the first embodiment of the present invention State transition diagram of call control task of handset in embodiment 1 of the present invention Flowchart of slave unit protocol processing task in the first embodiment of the present invention Flowchart of wireless transmission task in Embodiment 1 of the present invention Flowchart of merge processing in Embodiment 1 of the present invention Wireless frame configuration diagram for a wireless LAN telephone Configuration diagram of radio frame in Embodiment 1 of the present invention Flowchart of wireless reception task in Embodiment 1 of the present invention Flow chart of bridge task of base unit in Embodiment 1 of the present invention The figure which shows the relationship between the audio | voice packet and radio | wireless frame in Embodiment 1 of this invention. The figure which shows the relationship between the error and voice packet in Embodiment 1 of this invention Functional block diagram of handset in embodiment 2 of the present invention Functional block diagram of base unit in Embodiment 2 of the present invention Task configuration diagram of the slave unit in the second embodiment of the present invention Flowchart of slave unit measurement task in Embodiment 2 of the present invention Flowchart of slave device transmission task in the second embodiment of the present invention Relationship diagram between total delay amount and allowable total delay time in Embodiment 2 of the present invention The figure which shows the example of the content of the transmission packet queue in Embodiment 2 of this invention The flowchart of the merge process of the subunit | mobile_unit in Embodiment 2 of this invention Configuration diagram of radio frame in Embodiment 2 of the present invention Flowchart of reception task in Embodiment 2 of the present invention Flow chart of transmission task of base unit in Embodiment 2 of the present invention Functional block diagram of the slave unit in the third embodiment of the present invention Functional block diagram of base unit in Embodiment 3 of the present invention Flowchart of slave device transmission task in Embodiment 3 of the present invention Flowchart of reception task in Embodiment 3 of the present invention Flowchart of duplicate packet search processing in Embodiment 3 of the present invention Flow chart of transmission task of base unit in Embodiment 3 of the present invention The figure which shows the mode of transmission / reception of the radio | wireless frame in the conventional wireless LAN telephone apparatus.

Explanation of symbols

101 Operation Unit 102 Audio Input Unit 103 Audio Output Unit 104 Reception Buffer 105 Transmission Buffer 106 LAN Communication Unit 107 Wireless Communication Unit 108 RTC
109 Parameter storage unit 110 Codec unit 111 Transmission packet queue 112 Payload integration unit 113 Reception packet queue 114 Payload division unit 115 Transmission waiting time calculation unit 116 Call control unit 117 Protocol processing unit 118 Upper protocol analysis unit 119 Error rate determination unit 120 Wired -Wireless bridge unit 121 Network delay measurement unit 122 Reception history buffer 123 Duplicate packet search unit 130 Control unit 201 CPU
202 ROM
203 RAM
204 RTC
205 Baseband 206 RF
207 A / D
208 Microphone 209 D / A
210 Speaker 211 Keyboard 212 Codec 213 Network I / F

Claims (11)

Duplicate the generated voice packet, save one or more copies, and send one or more copies of one or more previously generated voice packets and recently generated voice packets in one radio frame at the time of transmission A wireless LAN telephone communication method, wherein the receiving side divides the packet into original packets. Allowable transmission delay time is calculated from the audio delay allowable time, audio codec period, audio codec delay, and the radio network scheduled transmission time determined by the predetermined network delay amount and the predetermined algorithm. Then, within the allowable range of the transmission waiting time, the voice packet is made redundant and a plurality of voice packets are transmitted together in one radio frame, and the reception side decomposes it into a plurality of redundant voice packets as before. A wireless LAN telephone communication method. A wireless LAN telephone communication method characterized in that interleaving is performed within an allowable delay time, and two or more non-consecutive voice packets among the redundant packets are collectively transmitted in one wireless frame. In order to measure the amount of network delay, a predetermined procedure is performed at a measurement time repeatedly obtained by a predetermined algorithm, the amount of network delay is measured, and the transmission waiting time is updated. The wireless LAN telephone communication method according to claim 2 or 3. 5. The wireless LAN telephone communication method according to claim 1, wherein when a voice packet duplicated in the reception history buffer is received, the voice packet is discarded. 6. The wireless LAN telephone communication method according to claim 1, wherein an upper protocol header is analyzed and a common part is omitted to form a frame. The communication method according to any one of claims 1 to 6 is implemented when the error rate of wireless communication is higher than a specified threshold value, and is not implemented otherwise. Wireless LAN telephone communication method. A wireless LAN telephone handset that implements the wireless LAN telephone communication method according to any one of claims 1 to 7. 8. A wireless LAN telephone base unit, characterized in that the wireless LAN telephone communication method according to claim 1 is realized. 8. A program that implements the wireless LAN telephone communication method according to claim 1. A wireless LAN telephone system, characterized in that the wireless LAN telephone communication method according to any one of claims 1 to 7 is realized.

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